Nate, tubes just arrived. I just inserted the RCA-boxed tube and queued 'Spyro Gyra - Telluride". Sounds good. 😎 Thanks again.
Finally, progress.
I'm going to try and get it temporarily wired up for testing some time this week, assuming the power stays on. But at least the fabrication is done which always seems to take the longest. My plan, ultimately is to repaint the chassis to hide some of the "stock" damage that came when I bought it. We'll see how that plan fares once I get to hear it. 😀
I'm going to try and get it temporarily wired up for testing some time this week, assuming the power stays on. But at least the fabrication is done which always seems to take the longest. My plan, ultimately is to repaint the chassis to hide some of the "stock" damage that came when I bought it. We'll see how that plan fares once I get to hear it. 😀
Nice looking build. It appears very professional. I like the clean layout and I especially like those big motor caps. The binding posts are impressive, too. Where's the underside photos?
I hear you about the plans for the final chassis finish. I don't think I've built an amp yet that received further cosmetic work once the music starts coming out. 😀
I hear you about the plans for the final chassis finish. I don't think I've built an amp yet that received further cosmetic work once the music starts coming out. 😀
Ty_Bower said:
Thanks Ty. No underside shots until I get some wiring done, maybe tonight if I'm lucky. And yeah, that's my fear about once the music starts as well. We'll see, it's taken so long to get this far I'm not sure I can bear the thought of taking it all apart.
n maher, looking at the photos i think you have got insulating washers on all the transformer bolts (to chassis). is that fundamentally necessary? - trying to pick up some tips for my build.
cheers
cheers
It's not necessary, but I'd highly recommend using some kind of bushing or washer to mechanically isolate the power transformer and filter choke from the chassis. They tend to vibrate a little bit due to the 60Hz magnetic field and the buzz can get transmitted into the chassis. Then the chassis acts as a sounding board and sometimes the noise is objectionable.
Mechanically isolating the output transformers doesn't really do anything, other than preserve the aesthetics of the amplifier.
Electrically, all the transformers should (must!) be connected to earth safety ground. In the unfortunate event of an insulation failure, you really don't want a "hot" transformer with over 450 volts DC (or AC) on it.
Mechanically isolating the output transformers doesn't really do anything, other than preserve the aesthetics of the amplifier.
Electrically, all the transformers should (must!) be connected to earth safety ground. In the unfortunate event of an insulation failure, you really don't want a "hot" transformer with over 450 volts DC (or AC) on it.
adamus said:
Ty pretty much nailed it. I'd only add that I just personally dislike hard-mounting transformers of any kind to a metal chassis.
Looking at the photos, I'd guess you are using the 300 series Hammond power transformer and the 5H 200mA Hammond choke? If so, that is the same combo that I am using on my Simple SE. As it was my first build, I did not bother (or know) to isolate the power transformer and choke. There is zero mechanical hum on my setup, and I am living in a 50Hz mains power country. I have on subsequent builds isolated the transformers though. For this I just used a sheet of 2-3mm rubber that I cut to fit the transformer base. I found the rubber sheet at an electronics shop in Singapore, it looked like it was meant to be a desk protector or something similar.
The build is looking great!
Chris
The build is looking great!
Chris
If I'd been the one spec'ing the parts that's the way I would have gone but as luck would have it as I was contemplating building a SimpleSE a full kit of parts showed up for sale here with all custom Electraprint iron. Being the sucker I am I jumped. So the power trafo is a 380-0-380/200mA primary, 5V/3A, 6.3V/4A secondaries and a 7H/175mA choke with bell ends to match the trafo. The outputs are 5K Electraprints as well.chrish said:
Thanks! I'm pretty pleased so far and am looking forward to lighting the lamps some time soon.
Looking at the amount of work you have done so far, I reckon you could get that thing fired up in basic triode mode in an hour or so. Looking at the back of your amp, does that IEC power socket have an integral fuse holder? If not, you will want to make sure you have a fuse in that cct .
Also looks like you have a set of JJ E34Ls in there too. That is the valve I keep going back to. Sounds great and not expensive.
Did you see my post about a switch for selecting different cathode bias resistors? I find this a great mod for experimenting with different output valves.
Cheers,
Chris
Also looks like you have a set of JJ E34Ls in there too. That is the valve I keep going back to. Sounds great and not expensive.
Did you see my post about a switch for selecting different cathode bias resistors? I find this a great mod for experimenting with different output valves.
Cheers,
Chris
Eh, I'm slow, it'll take longer than that. I have to wire the inputs to the pot (assuming I start with it in the loop), do all of the power wiring and then figure out how to wire the output trafos. This is my first build that uses output trafos so there's a bit of a learning curve. We'll see how much time I have to dedicate to it tonight and see what I can get done.chrish said:
Yes it does. I figure if I'm going to go through the annoyance of cutting a d-shaped hole I'm going to save myself the trouble of having to install a separate fuse holder.
Those are JJ's but they're 6L6s. I've got those, a set of EH EL34s and a pair of the Gold Lion reissue KT88s. Should be some fun tube rolling in my future.
I did. I've got a resistor in there now that should allow for some experimentation but I'm not sure if I'll go through the trouble of wiring up the variable resistor. We'll have to see how the initial setup goes and take it one step at a time.
I understand the reluctance to drill extra holes etc when you are so close. FWIW, three cathode resistors for each valve and a three position two pole switch were easier to wire up than the cathode feedback and triode/ultralineare selectors.
I found that the Russian 6L6s ran too hot with the standard 560R cathode resistor. Maybe the JJs are a little more robust or you selected a better value resistor to consider the 6L6s.
Let us know how it sounds.
Chris
I found that the Russian 6L6s ran too hot with the standard 560R cathode resistor. Maybe the JJs are a little more robust or you selected a better value resistor to consider the 6L6s.
Let us know how it sounds.
Chris
It's not just the drilling of holes, it's the Mouser order that I'd need to place to get the 2P3T switch along with ordering more resistors from yet another vendor (if I stick with the all boutique theme). All that would likely delay things until next year so for now I'm going to go the, uh, simple route. 😉chrish said:
I'll be sure to test the amp with the EL34s before even trying the 6L6's. And since I do have a 560R cathode resistor the 6L6's may just stay in their boxes for now.
Oh you can count on that.
Last night I did manage to install the final bits that I'll need to start wiring. These consisted of a terminal strip to use for the star ground, a ground post to serve as a single chassis ground location and I got the two 22uF Solen film caps that I'm using in place of C1 mounted. That last part was a bugger, it was the first time I've used cable ties to secure large axial caps but the end result was worth the effort. I'll try to post a bottom side picture tonight so folks can see what it looks like before the wiring begins.
Thanks for all the encouragement, it helps!
[edit]I can't believe that the forum softwhere treats "bug_ger" as a swear?
it's alive...
IT'S ALIVE!!!
Took me about 2hrs to temporarily wire it up for testing. So far it sounds excellent and is dead quiet (no hum, other than the power trafo) which seems like a huge success given the marginal wiring layout. I'll post up a few pictures tomorrow. Right now I'm exhausted and have ~8" of snow to look forward to tomorrow morning.
Thanks to everyone for all the help and inspiration.
IT'S ALIVE!!!
Took me about 2hrs to temporarily wire it up for testing. So far it sounds excellent and is dead quiet (no hum, other than the power trafo) which seems like a huge success given the marginal wiring layout. I'll post up a few pictures tomorrow. Right now I'm exhausted and have ~8" of snow to look forward to tomorrow morning.
Thanks to everyone for all the help and inspiration.
As promised.
Semi Finished Overall
Upskirt Overall
Ground Central
Shielded Input Wiring
The "No Electrolytics Zone"
And yes, I'm fully aware that I need to ground all of the trafos and chokes still. I also still have to wire up the pot and decide if I want to go through the hassle of having feedback and ultralinear switches on the amp. I think all of that will have to wait till next year while I concentrate on finishing up a couple of other projects.
Semi Finished Overall
Upskirt Overall
Ground Central
Shielded Input Wiring
The "No Electrolytics Zone"
And yes, I'm fully aware that I need to ground all of the trafos and chokes still. I also still have to wire up the pot and decide if I want to go through the hassle of having feedback and ultralinear switches on the amp. I think all of that will have to wait till next year while I concentrate on finishing up a couple of other projects.
n_maher, that is a very nice looking amplifier. I can put your pictures on the web page that I have of customers amps if you want. I have several more customers amps to post when I do the next web site update.
The "ground central" and "no electrolytic zone" are innovative methods that could be used by everybody.
I am curious as to the source of your blue transformer mounting grommets. The look easier to use than nylon shoulder washers.
I am temporarily located in northern West Virginia for the rest of the year. The rest of the snow from last week melted yesterday. The TV says that the next round will be here in 2 days. I would be floating in the pool if I was home😀
The "ground central" and "no electrolytic zone" are innovative methods that could be used by everybody.
I am curious as to the source of your blue transformer mounting grommets. The look easier to use than nylon shoulder washers.
I am temporarily located in northern West Virginia for the rest of the year. The rest of the snow from last week melted yesterday. The TV says that the next round will be here in 2 days. I would be floating in the pool if I was home😀
We might have to hold off on posting any pictures, after about an hour of use tonight the volume rapidly faded (i was sitting next to the amp and shut it off immediately). I checked the fuse, roached, but I was only using a 2A fuse which I think is boderline for this amp but it was what was close the first time I fired it up. Replaced it with a 4A fuse, poof, another bit for the landfill.tubelab.com said:
Unfortunately it's late so I can't do anything tonight but tomorrow I'll test the tubes that I was using since they were all used in some way shape of form but is there anything else that I can check outside of the visual things? Nothing looks harmed but I haven't had a look at the top side of the pcb yet. Nothing smelled burnt or smoked so I'm guessing all appears well on the top side. The come from McMaster Carr. I'll try and post up a part number for you tomorrow. Pete Millett recommended them to me (he used them on the original HA-2 amp that he sold) and I've used both the blue variety and a large black variety. I think they can be found pretty quickly by searching McM for vibration isolation grommet or something like that.
More tomorrow, hopefully good news.
Oh, and they're calling for another 12 to 18" of the white stuff tomorrow.
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